# Trigonometric functions¶

Let us do some maths here!

## No proofs¶

We include no proofs whatsoever.

## Integration¶

As the derivative of $$\sin x$$ is $$\cos x$$, and that of $$\cos x$$ is $$-\sin x$$, we have

$\int_{a}^{b}\cos x dx = \sin b - \sin a \int_{a}^{b}\sin x dx = \cos a - \cos b$

Isn’t that beautiful?